Chapter 1-5
What is the photoelectric scanning method in which the receiver responds only to the depolarized reflected light from a special reflector or polarized sensitive reflective tape?
Polarized
When properly biased, a silicon diode will conduct when more than ? is applied.
0.6 V
The diac has two terminals identified as ? and ? .
A1 / A2
What is the photoelectric scanning method in which the transmitter and receiver are placed opposite each other?
Direct
The ? is controlled by voltage.
FET
The triac is a half-wave device.
False
When a diode is properly biased to conduct, the depletion region will expand.
False
When the gate pulse is removed from an SCR, the SCR will stop conducting.
False
? devices are solid-state sensors that detect the presence of a magnetic field.
Hall effect
? proximity sensors can only detect metals that conduct current.
Inductive
A ? has three leads, identified as drain, source, and gate.
JFET
? are well-suited for switching operations.
JFETs
A semiconductor material with an excess of free electrons is called a(n) ? material.
N-type
A semiconductor material with a deficiency of free electrons is called a(n) ? material.
P-type
? devices are non-contact solid-state devices that use light to detect the presence of objects.
Photoelectric
? is the process of converting an AC voltage to a DC voltage.
Rectification
The negative and positive ions in the depletion region of a silicon diode creates an interior ? voltage of approximately 0.6 volts.
barrier
The center material of a bipolar junction transistor is called a ? .
base
Current can flow from anode to cathode in a diode if it is reversed biased and the ? voltage is reached.
breakdown
A(n) ? proximity sensor can detect a wide range of materials, including metals (ferrous and nonferrous), glass, plastics, and liquids.
capacitive
Proximity sensors that detect objects using an electrostatic field are known as ? devices.
capacitive
The size and dielectric properties of the object are the two factors that determine the effective sensing range of a ? proximity sensor.
capacitive
The N side of a PN junction diode is referred to as the ? .
cathode
The vertical line on the diode symbol, or the striped end of a diode, denotes the ? .
cathode
When a transistor operates as an open switch, it is in the ? region.
cutoff
When a transistor operates as a switch, it is in the ? region or ? region.
cutoff / saturation
The most common application for a zener diode is ? .
d. voltage regulation
The area between the P-type materials and the N-type materials of a single junction PN diode is known as the ? region.
depletion
Adding impurities to a pure material is known as the ? process.
doping
Reverse bias on a diode will cause the depletion region to ? .
expand
A(n) ? is used to provide a signal between two electrically isolated circuits.
optocoupler
The maximum reverse bias voltage a diode can withstand is known as ? voltage.
peak inverse
A ? is a PN junction device which allows reverse current flow when light energy is focused on the P-type material.
photodiode
Response time, sensitivity, operation margin, and light/dark operation are four parameters that are commonly used to describe the operation of ? devices.
photoelectric
A(n) ? conducts current as a function of light intensity.
phototransistor
The ? is a solid-state device that combines a photodiode and a transistor.
phototransistor
Current-sourcing outputs use the ? side of the DC output circuit as the switch leg to the load device.
positive
Capacitive, inductive and ultrasonic are three types of ? sensors that are based on the sensor's operating principles.
proximity
Since diodes conduct current flow in only one direction, they are commonly used to convert an AC voltage to a(n) ? DC voltage.
pulsating
The component present in a photoelectric device that detects the presence of the light source is a ? .
receiver
A photodiode operates with the external voltage source connected in a ? bias mode.
reverse
Zener diodes are designed to operate with a ? bias voltage.
reverse
When a transistor operates as a closed switch, it is in the ? region.
saturation
A(n) ? exhibits characteristics of both insulators and conductors.
semiconductor
A diode that has a low resistance at both polarities is ? .
shorted
Two common semiconductor materials are ? and ? .
silicon / germanium
Sensors that use an NPN transistor to switch DC loads are current- ? devices.
sinking
The sensor in an IEC Standard NPN device must be connected to provide a ? connection to the load.
sinking
Sensors that use a PNP transistor to switch DC loads are current- ? devices.
sourcing
The IEC Standard PNP device must be connected to provide a ? connection to the load.
sourcing
Amplification and ? are the two main operating functions of the transistor.
switching
What is the photoelectric scanning method in which the transmitter and receiver are housed in the same enclosure and in which a specialized scanning technique is used not only to determine when an object is moved into position but also to identify the specific location of the object?
Diffuse
A ? has three leads identified as base, collector, and emitter.
BJT
The ? is controlled by current.
BJT
? are used to determine if a semiconductor device's operational characteristics will be linear or non-linear over a range of voltage, current, or temperature values.
Characteristic curves
Electronic sensors with a(n) ? output interface can switch AC or DC without the specific polarity requirements for DC circuits.
Relay
? is measured by the number of light pulses per second that a photoelectric device transmits.
Response time
What is the photoelectric scanning method in which the transmitter and receiver are housed in the same enclosure and the transmitted beam is reflected back to the receiver from a reflector?
Retroreflective
A(n) ? has three leads, identified as anode, cathode, and gate.
SCR
? is the threshold value for received light to trigger a change in the output status of a photoelectric device.
Sensitivity
A diode is a semiconductor device that allows current to flow in only one direction.
True
A primary step in troubleshooting any of the sensors covered is to determine if the sensor has the correct operating input voltage.
True
Discrete mechanical sensors have contacts that open and close. Since discrete electronic sensors often do not have mechanical contacts, the output condition is described as activated or de-activated.
True
Electronic devices should be removed from the circuit before they are tested.
True
Since solid-state sensors use semiconductor circuits instead of contacts to switch the attached load, the load must match the voltage and current specifications for the sensor.
True
The SCR is a half-wave device.
True
The gate lead controls or triggers the SCR.
True
The output signal of a discrete sensor can only be on or off.
True
To test semiconductor devices, one must understand the cause and effect of forward-biasing a PN junction and reverse-biasing a PN junction.
True
Transistor circuits are identified by the terminal that is common to the input and the output.
True
When the width of the depletion region changes, in essence the resistance of the PN junction changes.
True
Zener voltage remains reasonably constant over a wide range of zener currents.
True
What type of proximity sensor emits a high frequency sound signal and detects the reflected sound from the object?
Ultrasonic
A diode is reversed biased when the ? is connected to the negative side of the external voltage source and the ? is connected to the positive side.
a. anode / cathode
A ? radiates energy at wavelengths of the visible light spectrum or in the infrared (non-visible) range when it is forward biased.
a. light-emitting diode
The ? modes enable a photoelectric sensor to detect whether a target is present or absent.
a. light/dark operation
When a transistor operates as a linear amplifier, it is operating in the ? region.
active
A photocell is a photoelectric device that only reacts to ? light.
ambient
The P side of a PN junction diode is referred to as the ? .
anode
Excess electrons can be added to intrinsic silicon or germanium by adding impurities such as ? , ? , and ? .
antimony / arsenic / bismuth
To conduct current, the semiconductor diode must be ? biased.
forward
For a BJT to operate as an amplifier, the base-emitter junction must be ? biased and the base-collector junction must be ? biased.
forward / reverse
A diode exhibits a ? resistance when it is reversed biased and a ? resistance when it is forward biased.
high / low
A ? operating margin indicates that a sensor will be reliable when ambient light conditions are variable.
higher
In an atom that has lost an electron, the place vacated by the free electron is referred to as a(n) ? .
hole
Adding gallium, boron, or indium to pure silicon or germanium will create a material with an excess of ? .
holes
Proximity sensors that detect objects using an electromagnetic field are known as ? devices.
inductive
The size of the object and the type of metal (ferrous or nonferrous) are two factors that determine the effective sensing range of a(n) ? proximity sensor.
inductive
A graph of device terminal current versus terminal voltage that produces a straight line indicates that resistance is ? through the range of values for voltage and current.
linear
A PN junction should exhibit a ? resistance when it is forward biased, and a ? resistance when it is reverse biased.
low / high
Current-sinking outputs use the ? side of the DC output circuit as the switch leg to the load device.
negative
A diode is forward biased when the cathode is connected to the ? side of the external voltage source and the anode is connected to the ? side.
negative / positive
A ? solid-state relay is an electronic device that performs the same function as an electromechanical relay.
non-programmable
Field-testing semiconductor devices focuses on using a(n) ? to determine if PN junctions in the device are functioning properly.
ohmmeter
A diode that has a high resistance at both polarities is ? .
open
The ratio of the available level of light at a photoelectric sensor's receiver to the minimum level of light required to trigger the sensor is the ? .
operating margin
The component present in a photoelectric device that provides a light source is a ? .
transmitter
The ? has three leads, identified as gate, main terminal 1, and main terminal 2.
triac
In a zener diode, the reverse breakdown voltage is referred to as ? voltage.
zener
The diac acts like two ? diodes in series; therefore, it is primarily used as a triggering device for other semiconductors.
zener
